U.S. patent number 10,791,558 [Application Number 15/850,539] was granted by the patent office on 2020-09-29 for techniques and apparatuses for autonomous resource selection for vehicle-to-everything (v2x) transmissions.
This patent grant is currently assigned to QUALCOMM Incorporated. The grantee listed for this patent is QUALCOMM Incorporated. Invention is credited to Scott Hoover, Haiqin Liu, Feng Lu, Yunsong Mu, Subramanya Rao, Arvind Santhanam, Taoufik Tani, Yuanbo Wang, Gang Xiao.
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United States Patent |
10,791,558 |
Santhanam , et al. |
September 29, 2020 |
Techniques and apparatuses for autonomous resource selection for
vehicle-to-everything (V2X) transmissions
Abstract
Certain aspects of the present disclosure generally relate to
wireless communication. In some aspects, a user equipment (UE) may
determine a limit on a number of resource blocks (RBs) permitted to
be used for a vehicle-to-everything (V2X) transmission by the UE;
may determine, based at least in part on the limit, one or more
parameters for the V2X transmission, wherein the one or more
parameters include at least one of a modulation and coding scheme
(MCS) for the V2X transmission, a number of transport blocks (TBs)
for the V2X transmission, a number of RBs per TB for the V2X
transmission, or a retransmission configuration for the V2X
transmission; and may transmit the V2X transmission based at least
in part on the one or more parameters. Numerous other aspects are
provided.
Inventors: |
Santhanam; Arvind (San Diego,
CA), Hoover; Scott (Del Mar, CA), Mu; Yunsong (La
Jolla, CA), Wang; Yuanbo (San Diego, CA), Xiao; Gang
(San Diego, CA), Liu; Haiqin (San Diego, CA), Rao;
Subramanya (Sunnyvale, CA), Tani; Taoufik (San Diego,
CA), Lu; Feng (Santa Clara, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Assignee: |
QUALCOMM Incorporated (San
Diego, CA)
|
Family
ID: |
1000005085146 |
Appl.
No.: |
15/850,539 |
Filed: |
December 21, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190104525 A1 |
Apr 4, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62567045 |
Oct 2, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
4/40 (20180201); H04W 72/0486 (20130101); H04W
4/44 (20180201); H04W 72/048 (20130101); H04W
28/0252 (20130101); H04W 72/02 (20130101); H04L
1/1825 (20130101); H04L 1/0003 (20130101); H04W
4/02 (20130101); H04L 1/0009 (20130101) |
Current International
Class: |
H04W
72/04 (20090101); H04L 1/18 (20060101); H04W
4/44 (20180101); H04W 72/02 (20090101); H04W
28/02 (20090101); H04W 4/40 (20180101); H04L
1/00 (20060101); H04W 4/02 (20180101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2016092528 |
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Jun 2016 |
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WO |
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WO-2017039417 |
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Mar 2017 |
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WO |
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WO-2017052690 |
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Mar 2017 |
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WO |
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Other References
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R2-1700929--Congestion Control for Sidelink-based V2X, 3rd
Generation Partnership Project (3GPP), Mobile Competence Centre;
650, Route Des Lucioles; F-06921 Sophia-Antipolis Cedex; FRA, vol.
RAN WG2, No. Athens, Greece; Feb. 13, 2017-Feb. 17, 2017, Feb. 12,
2017, XP051211703, 10 pages, Retrieved from the Internet: URL:
http://www.3gpp.org/ftp/Meetings_3GPP_SYNC/RAN2/Docs/ [retrieved on
Feb. 12, 2017]. cited by applicant .
Intel Corporation: "Sidelink Congestion Control for V2X Services,"
3GPP Draft; R1-1611925 Intel--V2V Congestion, 3rd Generation
Partnership Project (3GPP), Mobile Competence Centre; 650, Route
Des Lucioles; F-06921 Sophia-Antipolis Cedex; France, vol. RAN WG1,
No. Reno, USA; Nov. 14, 2016-Nov. 18, 2016, Nov. 13, 2016,
XP051175891, 6 pages, Retrieved from the Internet: URL:
http://www.3gpp.org/ftp/Meetings_3GPP_SYNC/RAN1/Docs/ [retrieved on
Nov. 13, 2016]. cited by applicant .
International Search Report and Written
Opinion--PCT/US2018/043924--ISA/EPO--dated Oct. 5, 2018. cited by
applicant .
LG Electronics: "Discussion on UE Behavior in Congestion Control,"
3GPP Draft; R1-1611741, UE Behavior in Congestion Control V1, 3rd
Generation Partnership Project (3GPP), Mobile Competence Centre;
650, Route Des Lucioles; F-06921 Sophia-Antipolis Cedex; France,
vol. RAN WG1, No. Reno USA; Nov. 14. 2016-Nov. 18, 2016, Nov. 13,
2016, XP051175711, 4 Pages, Retrieved from the Internet: URL:
http://www.3gpp.org/ftp/Meetings_3GPP_SYNC/RAN1/Docs/ [retrieved on
Nov. 13, 2016]. cited by applicant .
Qualcomm Incorporated: "Congestion Control for V2V,"3GPP Draft;
R2-168593_V2V_DCC, 3rd Generation Partnership Project (3GPP),
Mobile Competence Centre; 650, Route Des Lucioles; F-06921
Sophia-Antipolis Cedex; France, vol. RAN WG2, No. Reno, USA; Nov.
14, 2016-Nov. 18, 2016, Nov. 13, 2016, XP051178163, 14 pages,
Retrieved from the Internet: URL:
http://www.3gpp.org/ftp/Meetings_3GPP_SYNC/RAN2/Docs/ [retrieved on
Nov. 13, 2016]. cited by applicant.
|
Primary Examiner: Cho; Un C
Assistant Examiner: Chang; Yu-Wen
Attorney, Agent or Firm: Harrity & Harrity, LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS UNDER 35 U.S.C. .sctn.
119
This application claims priority to Provisional Patent Application
No. 62/567,045, filed on Oct. 2, 2017, entitled "TECHNIQUES AND
APPARATUSES FOR AUTONOMOUS RESOURCE SELECTION FOR
VEHICLE-TO-EVERYTHING (V2X) TRANSMISSIONS," which is hereby
expressly incorporated by reference herein.
Claims
What is claimed is:
1. A method of wireless communication performed by a user equipment
(UE), comprising: determining a limit on a number of resource
blocks (RBs) permitted to be used for a vehicle-to-everything (V2X)
transmission by the UE, wherein the limit is determined based at
least in part on a congestion level of a sidelink channel via which
the V2X transmission is to be transmitted; determining, based at
least in part on the limit, a combination of parameters for the V2X
transmission, wherein the combination of parameters for the V2X
transmission includes a modulation and coding scheme (MCS) for the
V2X transmission and includes at least one of a number of transport
blocks (TBs) for the V2X transmission, a number of RBs per TB for
the V2X transmission, or a retransmission configuration for the V2X
transmission, wherein determining the combination of parameters for
the V2X transmission comprises: testing an initial combination of
parameters for the V2X transmission to determine if the initial
combination of parameters for the V2X transmission satisfies the
limit on the number of RBs permitted to be used for the V2X
transmission by the UE, when the initial combination of parameters
for the V2X transmission does not satisfy the limit on the number
of RBs permitted to be used for the V2X transmission by the UE,
testing a different combination of parameters for the V2X
transmission, the different combination of parameters for the V2X
transmission having at least one of a different retransmission
configuration than the initial combination, a smaller number of TBs
than the initial combination, or a smaller number of RBs per TB
than the initial combination, and selecting the different
combination of parameters for the V2X transmission as the
combination of parameters for the V2X transmission when the
different combination of parameters for the V2X transmission
satisfies the limit on the number of RBs permitted to be used for
the V2X transmission by the UE; and transmitting the V2X
transmission based at least in part on the combination of
parameters for the V2X transmission.
2. The method of claim 1, wherein one or more parameters, included
in the combination of parameters for the V2X transmission, are
determined based at least in part on one or more dynamic factors
associated with the UE or a wireless network via which the V2X
transmission is transmitted.
3. The method of claim 1, wherein one or more parameters, included
in the combination of parameters for the V2X transmission, are
determined based at least in part on a network traffic demand
associated with one or more applications of the UE.
4. The method of claim 1, wherein one or more parameters, included
in the combination of parameters for the V2X transmission, are
determined based at least in part on a congestion level associated
with a wireless network via which the V2X transmission is to be
transmitted.
5. The method of claim 1, wherein one or more parameters, included
in the combination of parameters for the V2X transmission, are
determined based at least in part on a carrier frequency on which
the V2X transmission is to be transmitted.
6. The method of claim 1, wherein one or more parameters, included
in the combination of parameters for the V2X transmission, are
determined based at least in part on a priority of the V2X
transmission compared to a priority of at least one other V2X
transmission.
7. The method of claim 1, wherein one or more parameters, included
in the combination of parameters for the V2X transmission, are
determined based at least in part on a velocity of the UE.
8. The method of claim 1, wherein one or more parameters, included
in the combination of parameters for the V2X transmission, are
determined based at least in part on a topography of a location of
the UE.
9. The method of claim 1, wherein one or more parameters, included
in the combination of parameters for the V2X transmission, are
determined based at least in part on a location of the UE.
10. The method of claim 1, wherein one or more parameters, included
in the combination of parameters for the V2X transmission, are
determined to maximize a range of the V2X transmission subject to
the limit on the number of RBs permitted to be used for the V2X
transmission by the UE.
11. The method of claim 1, wherein one or more parameters, included
in the combination of parameters for the V2X transmission, are
determined based at least in part on at least one of: a number of
bits of the V2X transmission, a deadline for transmission of the
V2X transmission, a semi-persistent scheduling period associated
with the V2X transmission, or some combination thereof.
12. The method of claim 1, wherein one or more parameters, included
in the combination of parameters for the V2X transmission, are
determined based at least in part on a default MCS associated with
the UE or a default combination of parameters for the V2X
transmission associated with the UE.
13. The method of claim 1, further comprising: determining a
plurality of resource block requirements corresponding to a
plurality of combinations of parameters; and determining the
combination of parameters for the V2X transmission based at least
in part on comparing the plurality of resource block requirements
to the limit on the number of RBs permitted to be used for the V2X
transmission by the UE.
14. The method of claim 13, wherein a resource block requirement,
of the plurality of resource block requirements, indicates a number
of resource blocks required to transmit the V2X transmission using
a particular combination of an MCS, a number of TBs, a number of
RBs, and a retransmission configuration.
15. The method of claim 1, wherein determining the combination of
parameters for the V2X transmission comprises: determining that a
first MCS, selected by the UE, exceeds a peak MCS permitted to be
used by the UE; determining a second MCS based at least in part on
determining that the first MCS exceeds the peak MCS; determining
that the second MCS does not exceed the peak MCS; and wherein
transmitting the V2X transmission comprises transmitting the V2X
transmission using the second MCS based at least in part on
determining that the second MCS does not exceed the peak MCS.
16. The method of claim 15, wherein the second MCS is determined
after waiting a threshold amount of time or determining that a
condition associated with the limit on the number of RBs permitted
to be used for the V2X transmission by the UE has changed.
17. The method of claim 1, wherein the combination of parameters
for the V2X transmission include the retransmission configuration,
wherein the retransmission configuration enables retransmission of
the V2X transmission; and wherein determining the combination of
parameters for the V2X transmission comprises selecting the lowest
MCS value that satisfies the limit on the number of RBs permitted
to be used for the V2X transmission by the UE with retransmission
enabled.
18. The method of claim 1, wherein the combination of parameters
for the V2X transmission include the retransmission configuration,
wherein the retransmission configuration disables retransmission of
the V2X transmission; and wherein determining the combination of
parameters for the V2X transmission comprises selecting the lowest
MCS value that satisfies the limit on the number of RBs permitted
to be used for the V2X transmission by the UE with retransmission
disabled.
19. The method of claim 1, wherein the combination of parameters
for the V2X transmission include the retransmission configuration;
and wherein the method further comprises: determining a first set
of parameters that includes a first MCS that satisfies the limit on
the number of RBs permitted to be used for the V2X transmission by
the UE with the retransmission configuration configured to enable
retransmission of the V2X transmission; determining a second set of
parameters that includes a second MCS that satisfies the limit on
the number of RBs permitted to be used for the V2X transmission by
the UE with the retransmission configuration configured to disable
retransmission of the V2X transmission; estimating a first range
for the V2X transmission using the first set of parameters;
estimating a second range for the V2X transmission using the second
set of parameters; and wherein determining the combination of
parameters for the V2X transmission comprises selecting one of the
first set of parameters or the second set of parameters based at
least in part on comparing the first range and the second
range.
20. A user equipment (UE) for wireless communication, comprising:
memory; and one or more processors operatively coupled to the
memory, the memory and the one or more processors configured to:
determine a limit on a number of resource blocks (RBs) permitted to
be used for a vehicle-to-everything (V2X) transmission by the UE,
wherein the limit is determined based at least in part on a
congestion level of a sidelink channel via which the V2X
transmission is to be transmitted; determine, based at least in
part on the limit, a combination of parameters for the V2X
transmission, wherein the combination of parameters for the V2X
transmission include a modulation and coding scheme (MCS) for the
V2X transmission and includes at least one of a number of transport
blocks (TB s) for the V2X transmission, a number of RBs per TB for
the V2X transmission, or a retransmission configuration for the V2X
transmission, wherein the one or more processors, when determining
the combination of parameters for the V2X transmission, are to:
test an initial combination of parameters for the V2X transmission
to determine if the initial combination of parameters for the V2X
transmission satisfies the limit on the number of RBs permitted to
be used for the V2X transmission by the UE, and when the initial
combination of parameters for the V2X transmission does not satisfy
the limit on the number of RBs permitted to be used for the V2X
transmission by the UE, test a different combination of parameters
for the V2X transmission, the different combination of parameters
for the V2X transmission having at least one of a different
retransmission configuration than the initial combination, a
smaller number of TBs than the initial combination, or a smaller
number of RBs per TB than the initial combination, and select the
different combination of parameters for the V2X transmission as the
combination of parameters for the V2X transmission when the
different combination of parameters for the V2X transmission
satisfies the limit on the number of RBs permitted to be used for
the V2X transmission by the UE; and transmit the V2X transmission
based at least in part on the combination of parameters for the V2X
transmission.
21. The UE of claim 20, wherein one or more parameters, included in
the combination of parameters for the V2X transmission, are
determined based at least in part on one or more of: a dynamic
factor associated with the UE or a wireless network via which the
V2X transmission is transmitted, a network traffic demand
associated with one or more applications of the UE, the congestion
level of the sidelink channel, a carrier frequency on which the V2X
transmission is to be transmitted, a priority of the V2X
transmission compared to a priority of at least one other V2X
transmission, a velocity of the UE, a topography of a location of
the UE, a location of the UE, a number of bits of the V2X
transmission, a priority of the V2X transmission, a deadline for
transmission of the V2X transmission, a semi-persistent scheduling
period associated with the V2X transmission, a default MCS
associated with the UE or a default combination of parameters for
the V2X transmission associated with the UE, or some combination
thereof.
22. The UE of claim 20, wherein one or more parameters, included in
the combination of parameters for the V2X transmission, are
determined to maximize a range of the V2X transmission subject to
the limit on the number of RBs permitted to be used for the V2X
transmission by the UE.
23. The UE of claim 20, wherein the memory and the one or more
processors are further configured to: determine a plurality of
resource block requirements corresponding to a plurality of
combinations of parameters; and determine the combination of
parameters for the V2X transmission based at least in part on
comparing the plurality of resource block requirements to the limit
on the number of RBs permitted to be used for the V2X transmission
by the UE.
24. The UE of claim 20, wherein the memory and the one or more
processors, when determining the combination of parameters for the
V2X transmission, are configured to: determine that a first MCS,
selected by the UE, exceeds a peak MCS permitted to be used by the
UE; determine a second MCS based at least in part on determining
that that the first MCS exceeds the peak MCS; determine that the
second MCS does not exceed the peak MCS; and wherein the memory and
the one or more processors, when transmitting the V2X transmission,
are configured to transmit the V2X transmission using the second
MCS based at least in part on determining that the second MCS does
not exceed the peak MCS.
25. The UE of claim 24, wherein the second MCS is determined after
waiting a threshold amount of time or determining that a condition
associated with the limit on the number of RBs permitted to be used
for the V2X transmission by the UE has changed.
26. The UE of claim 20, wherein the combination of parameters for
the V2X transmission include the retransmission configuration,
wherein the retransmission configuration enables retransmission of
the V2X transmission; and wherein the memory and the one or more
processors, when determining the combination of parameters for the
V2X transmission, are configured to select the lowest MCS value
that satisfies the limit on the number of RBs permitted to be used
for the V2X transmission by the UE with retransmission enabled.
27. The UE of claim 20, wherein the combination of parameters for
the V2X transmission include the retransmission configuration,
wherein the retransmission configuration disables retransmission of
the V2X transmission; and wherein the memory and the one or more
processors, when determining the combination of parameters for the
V2X transmission, are configured to select the lowest MCS value
that satisfies the limit on the number of RBs permitted to be used
for the V2X transmission by the UE with retransmission
disabled.
28. The UE of claim 20, wherein the combination of parameters for
the V2X transmission include the retransmission configuration; and
wherein the memory and the one or more processors are further
configured to: determine a first set of parameters that includes a
first MCS that satisfies the limit on the number of RBs permitted
to be used for the V2X transmission by the UE with the
retransmission configuration configured to enable retransmission of
the V2X transmission; determine a second set of parameters that
includes a second MCS that satisfies the limit on the number of RBs
permitted to be used for the V2X transmission by the UE with the
retransmission configuration configured to disable retransmission
of the V2X transmission; estimate a first range for the V2X
transmission using the first set of parameters; estimate a second
range for the V2X transmission using the second set of parameters;
and wherein the memory and the one or more processors, when
determining the combination of parameters for the V2X transmission,
are configured to select one of the first set of parameters or the
second set of parameters based at least in part on comparing the
first range and the second range.
29. An apparatus for wireless communication, comprising: means for
determining a limit on a number of resource blocks (RBs) permitted
to be used for a vehicle-to-everything (V2X) transmission by the
apparatus, wherein the limit is determined based at least in part
on a congestion level of a sidelink channel via which the V2X
transmission is to be transmitted; means for determining, based at
least in part on the limit, a combination of parameters for the V2X
transmission, wherein the combination of parameters for the V2X
transmission includes a modulation and coding scheme (MCS) for the
V2X transmission and includes at least one of a number of transport
blocks (TBs) for the V2X transmission, a number of RBs per TB for
the V2X transmission, or a retransmission configuration for the V2X
transmission, wherein the means for determining the combination of
parameters for the V2X transmission includes: means for testing an
initial combination of parameters for the V2X transmission to
determine if the initial combination of parameters for the V2X
transmission satisfies the limit on the number of RBs permitted to
be used for the V2X transmission by the apparatus, when the initial
combination of parameters for the V2X transmission does not satisfy
the limit on the number of RBs permitted to be used for the V2X
transmission by the UE, means for testing a different combination
of parameters for the V2X transmission, the different combination
of parameters for the V2X transmission having at least one of a
different retransmission configuration than the initial
combination, a smaller number of TBs than the initial combination,
or a smaller number of RBs per TB than the initial combination, and
means for selecting the different combination of parameters for the
V2X transmission as the combination of parameters for the V2X
transmission when the different combination of parameters for the
V2X transmission satisfies the limit on the number of RBs permitted
to be used for the V2X transmission by the apparatus; and means for
transmitting the V2X transmission based at least in part on the
combination of parameters for the V2X transmission.
30. A non-transitory computer-readable medium storing instructions
for wireless communication, the instructions comprising: one or
more instructions that, when executed by one or more processors of
a user equipment (UE), cause the one or more processors to:
determine a limit on a number of resource blocks (RBs) permitted to
be used for a vehicle-to-everything (V2X) transmission by the UE,
wherein the limit is determined based at least in part on a
congestion level of a sidelink channel via which the V2X
transmission is to be transmitted; determine, based at least in
part on the limit, a combination of parameters for the V2X
transmission, wherein the combination of parameters for the V2X
transmission includes a modulation and coding scheme (MCS) for the
V2X transmission and includes at least one of a number of transport
blocks (TBs) for the V2X transmission, a number of RBs per TB for
the V2X transmission, or a retransmission configuration for the V2X
transmission, wherein the one or more instructions, that cause the
one or more processors to determine the combination of parameters
for the V2X transmission, cause the one or more processors to: test
an initial combination of parameters for the V2X transmission to
determine if the initial combination of parameters for the V2X
transmission satisfies the limit on the number of RBs permitted to
be used for the V2X transmission by the UE, when the initial
combination of parameters for the V2X transmission does not satisfy
the limit on the number of RBs permitted to be used for the V2X
transmission by the UE, test a different combination of parameters
for the V2X transmission, the different combination of parameters
for the V2X transmission having at least one of a different
retransmission configuration than the initial combination, a
smaller number of TBs than the initial combination, or a smaller
number of RBs per TB than the initial combination, and select the
different combination of parameters for the V2X transmission as the
combination of parameters for the V2X transmission when the
different combination of parameters for the V2X transmission
satisfies the limit on the number of RBs permitted to be used for
the V2X transmission by the UE; and transmit the V2X transmission
based at least in part on the combination of parameters for the V2X
transmission.
Description
TECHNICAL FIELD
Aspects of the present disclosure generally relate to wireless
communication, and more particularly to techniques and apparatuses
for autonomous resource selection for V2X transmissions.
INTRODUCTION
Wireless communication systems are widely deployed to provide
various telecommunication services, such as telephony, video, data,
messaging, and broadcasts. Typical wireless communication systems
may employ multiple-access technologies capable of supporting
communication with multiple users by sharing available system
resources (e.g., bandwidth, transmit power, and/or the like).
Examples of such multiple-access technologies include code division
multiple access (CDMA) systems, time division multiple access
(TDMA) systems, frequency-division multiple access (FDMA) systems,
orthogonal frequency-division multiple access (OFDMA) systems,
single-carrier frequency-division multiple access (SC-FDMA)
systems, time division synchronous code division multiple access
(TD-SCDMA) systems, and Long Term Evolution (LTE) systems.
LTE/LTE-Advanced is a set of enhancements to the Universal Mobile
Telecommunications System (UMTS) mobile standard promulgated by the
Third Generation Partnership Project (3GPP).
A wireless communication network may include a number of base
stations (BSs) that can support communication for a number of user
equipment (UEs). A user equipment (UE) may communicate with a base
station (BS) via a downlink and an uplink. The downlink (or forward
link) refers to the communication link from the BS to the UE, and
the uplink (or reverse link) refers to the communication link from
the UE to the BS. As will be described in more detail herein, a BS
may be referred to as a Node B, a gNB, an access point (AP), a
radio head, a transmit receive point (TRP), a new radio (NR) BS, a
5G Node B, and/or the like.
The above multiple access technologies have been adopted in various
telecommunication standards to provide a common protocol that
enables different user equipment to communicate on a municipal,
national, regional, and even global level. New radio (NR), which
may also be referred to as 5G, is a set of enhancements to the LTE
mobile standard promulgated by the 3GPP. NR is designed to better
support mobile broadband Internet access by improving spectral
efficiency, lowering costs, improving services, making use of new
spectrum, and better integrating with other open standards using
orthogonal frequency division multiplexing (OFDM) with a cyclic
prefix (CP) (CP-OFDM) on the downlink (DL), using CP-OFDM and/or
SC-FDM (e.g., also known as discrete Fourier transform spread OFDM
(DFT-s-OFDM)) on the uplink (UL), as well as supporting
beamforming, multiple-input multiple-output (MIMO) antenna
technology, and carrier aggregation. However, as the demand for
mobile broadband access continues to increase, there exists a need
for further improvements in LTE and NR technologies. Preferably,
these improvements should be applicable to other multiple access
technologies and the telecommunication standards that employ these
technologies.
SUMMARY
In some aspects, a method of wireless communication, performed by a
user equipment (UE), may include determining a limit on a number of
resource blocks (RBs) permitted to be used for a
vehicle-to-everything (V2X) transmission by the UE; determining,
based at least in part on the limit, one or more parameters for the
V2X transmission, wherein the one or more parameters include at
least one of a modulation and coding scheme (MCS) for the V2X
transmission, a number of transport blocks (TBs) for the V2X
transmission, a number of RBs per TB for the V2X transmission, or a
retransmission configuration for the V2X transmission; and
transmitting the V2X transmission based at least in part on the one
or more parameters.
In some aspects, a UE for wireless communication may include memory
and one or more processors operatively coupled to the memory. The
memory and the one or more processors may be configured to
determine a limit on a number of resource blocks (RBs) permitted to
be used for a vehicle-to-everything (V2X) transmission by the UE;
determine, based at least in part on the limit, one or more
parameters for the V2X transmission, wherein the one or more
parameters include at least one of a modulation and coding scheme
(MCS) for the V2X transmission, a number of transport blocks (TBs)
for the V2X transmission, a number of RBs per TB for the V2X
transmission, or a retransmission configuration for the V2X
transmission; and transmit the V2X transmission based at least in
part on the one or more parameters.
In some aspects, a non-transitory computer-readable medium may
store one or more instructions for wireless communication. The one
or more instructions, when executed by one or more processors of a
UE, may cause the one or more processors to determine a limit on a
number of resource blocks (RBs) permitted to be used for a
vehicle-to-everything (V2X) transmission by the UE; determine,
based at least in part on the limit, one or more parameters for the
V2X transmission, wherein the one or more parameters include at
least one of a modulation and coding scheme (MCS) for the V2X
transmission, a number of transport blocks (TBs) for the V2X
transmission, a number of RBs per TB for the V2X transmission, or a
retransmission configuration for the V2X transmission; and transmit
the V2X transmission based at least in part on the one or more
parameters.
In some aspects, an apparatus for wireless communication may
include means for determining a limit on a number of resource
blocks (RBs) permitted to be used for a vehicle-to-everything (V2X)
transmission by the apparatus; means for determining, based at
least in part on the limit, one or more parameters for the V2X
transmission, wherein the one or more parameters include at least
one of a modulation and coding scheme (MCS) for the V2X
transmission, a number of transport blocks (TBs) for the V2X
transmission, a number of RBs per TB for the V2X transmission, or a
retransmission configuration for the V2X transmission; and means
for transmitting the V2X transmission based at least in part on the
one or more parameters.
Aspects generally include a method, apparatus, system, computer
program product, non-transitory computer-readable medium, user
equipment, wireless communication device, and processing system as
substantially described herein with reference to and as illustrated
by the accompanying drawings and specification.
The foregoing has outlined rather broadly the features and
technical advantages of examples according to the disclosure in
order that the detailed description that follows may be better
understood. Additional features and advantages will be described
hereinafter. The conception and specific examples disclosed may be
readily utilized as a basis for modifying or designing other
structures for carrying out the same purposes of the present
disclosure. Such equivalent constructions do not depart from the
scope of the appended claims. Characteristics of the concepts
disclosed herein, both their organization and method of operation,
together with associated advantages will be better understood from
the following description when considered in connection with the
accompanying figures. Each of the figures is provided for the
purpose of illustration and description, and not as a definition of
the limits of the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above-recited features of the
present disclosure can be understood in detail, a more particular
description, briefly summarized above, may be had by reference to
aspects, some of which are illustrated in the appended drawings. It
is to be noted, however, that the appended drawings illustrate only
certain typical aspects of this disclosure and are therefore not to
be considered limiting of its scope, for the description may admit
to other equally effective aspects. The same reference numbers in
different drawings may identify the same or similar elements.
FIG. 1 is a block diagram conceptually illustrating an example of a
wireless communication network, in accordance with certain aspects
of the present disclosure.
FIG. 2 is a block diagram conceptually illustrating an example of a
base station in communication with a user equipment (UE) in a
wireless communication network, in accordance with certain aspects
of the present disclosure.
FIG. 3 is a block diagram conceptually illustrating an example of
V2X communications via a sidelink, in accordance with certain
aspects of the present disclosure.
FIGS. 4 and 5 are diagrams illustrating examples of autonomous
resource selection for V2X transmissions, in accordance with
various aspects of the present disclosure.
FIG. 6 is a diagram illustrating an example process performed, for
example, by a user equipment, in accordance with various aspects of
the present disclosure.
DETAILED DESCRIPTION
In a vehicle-to-everything (V2X) wireless communication system, UEs
may communicate directly using device-to-device communication, also
known as sidelink communication, without using a base station as an
intermediary. In some cases, a UE may operate using transmission
mode 4, where resource selection and/or scheduling is performed by
the UE rather than a base station. In some aspects, the UE may
perform resource selection and/or scheduling by measuring one or
more sidelink channels, by decoding sidelink control information
(SCI) that indicates channel availability, by determining a channel
busy rate (CBR) associated with various sidelink channels, and/or
the like.
In transmission mode 4, a UE may generate sidelink grants, and may
transmit the sidelink grants in SCI. A sidelink grant may indicate,
for example, one or more parameters (e.g., transmission parameters)
to be used for an upcoming V2X transmission (e.g., a V2X data
transmission), such as one or more resource blocks to be used for
the upcoming V2X transmission, one or more subframes to be used for
the upcoming V2X transmission, a modulation and coding scheme (MCS)
to be used for the upcoming V2X transmission, and/or the like.
In V2X communication systems, conditions of the sidelink channel
used to carry V2X communications can vary widely and change quickly
due to the high mobility of vehicles and UEs associated with the
vehicles, large variations in vehicle traffic at different times of
day and in different locations, a wide variety of topographies that
the vehicles may traverse (e.g., dense urban environments, hilly
environments, flat environments, etc.), and/or the like.
Furthermore, V2X communication systems need to be highly reliable
due to mission critical safety issues associated with, for example,
autonomous vehicles. Some techniques and apparatuses described
herein improve performance of V2X communication systems by
dynamically determining parameters for V2X transmissions based at
least in part on dynamic factors associated with one or more
vehicles, the sidelink channel, and/or the like.
Various aspects of the disclosure are described more fully
hereinafter with reference to the accompanying drawings. This
disclosure may, however, be embodied in many different forms and
should not be construed as limited to any specific structure or
function presented throughout this disclosure. Rather, these
aspects are provided so that this disclosure will be thorough and
complete, and will fully convey the scope of the disclosure to
those skilled in the art. Based on the teachings herein one skilled
in the art should appreciate that the scope of the disclosure is
intended to cover any aspect of the disclosure disclosed herein,
whether implemented independently of or combined with any other
aspect of the disclosure. For example, an apparatus may be
implemented or a method may be practiced using any number of the
aspects set forth herein. In addition, the scope of the disclosure
is intended to cover such an apparatus or method which is practiced
using other structure, functionality, or structure and
functionality in addition to or other than the various aspects of
the disclosure set forth herein. It should be understood that any
aspect of the disclosure disclosed herein may be embodied by one or
more elements of a claim.
Several aspects of telecommunication systems will now be presented
with reference to various apparatuses and techniques. These
apparatuses and techniques will be described in the following
detailed description and illustrated in the accompanying drawings
by various blocks, modules, components, circuits, steps, processes,
algorithms, and/or the like (collectively referred to as
"elements"). These elements may be implemented using hardware,
software, or combinations thereof. Whether such elements are
implemented as hardware or software depends upon the particular
application and design constraints imposed on the overall
system.
It is noted that while aspects may be described herein using
terminology commonly associated with 3G and/or 4G wireless
technologies, aspects of the present disclosure can be applied in
other generation-based communication systems, such as 5G and later,
including NR technologies.
FIG. 1 is a diagram illustrating a network 100 in which aspects of
the present disclosure may be practiced. The network 100 may be an
LTE network, a 5G or NR network, and/or the like. Wireless network
100 may include a number of BSs 110 (shown as BS 110a, BS 110b, BS
110c, and BS 110d) and other network entities. A BS is an entity
that communicates with user equipment (UEs) and may also be
referred to as a base station, a NR BS, a Node B, a gNB, a 5G node
B (NB), an access point, a transmit receive point (TRP), and/or the
like. Each BS may provide communication coverage for a particular
geographic area. In 3GPP, the term "cell" can refer to a coverage
area of a BS and/or a BS subsystem serving this coverage area,
depending on the context in which the term is used.
A BS may provide communication coverage for a macro cell, a pico
cell, a femto cell, and/or another type of cell. A macro cell may
cover a relatively large geographic area (e.g., several kilometers
in radius) and may allow unrestricted access by UEs with service
subscription. A pico cell may cover a relatively small geographic
area and may allow unrestricted access by UEs with service
subscription. A femto cell may cover a relatively small geographic
area (e.g., a home) and may allow restricted access by UEs having
association with the femto cell (e.g., UEs in a closed subscriber
group (CSG)). A BS for a macro cell may be referred to as a macro
BS. A BS for a pico cell may be referred to as a pico BS. A BS for
a femto cell may be referred to as a femto BS or a home BS. In the
example shown in FIG. 1, a BS 110a may be a macro BS for a macro
cell 102a, a BS 110b may be a pico BS for a pico cell 102b, and a
BS 110c may be a femto BS for a femto cell 102c. A BS may support
one or multiple (e.g., three) cells. The terms "eNB", "base
station", "NR BS", "gNB", "TRP", "AP", "node B", "5G NB", and
"cell" may be used interchangeably herein.
In some examples, a cell may not necessarily be stationary, and the
geographic area of the cell may move according to the location of a
mobile BS. In some examples, the BSs may be interconnected to one
another and/or to one or more other BSs or network nodes (not
shown) in the access network 100 through various types of backhaul
interfaces such as a direct physical connection, a virtual network,
and/or the like using any suitable transport network.
Wireless network 100 may also include relay stations. A relay
station is an entity that can receive a transmission of data from
an upstream station (e.g., a BS or a UE) and send a transmission of
the data to a downstream station (e.g., a UE or a BS). A relay
station may also be a UE that can relay transmissions for other
UEs. In the example shown in FIG. 1, a relay station 110d may
communicate with macro BS 110a and a UE 120d in order to facilitate
communication between BS 110a and UE 120d. A relay station may also
be referred to as a relay BS, a relay base station, a relay, and/or
the like.
Wireless network 100 may be a heterogeneous network that includes
BSs of different types, e.g., macro BSs, pico BSs, femto BSs, relay
BSs, and/or the like. These different types of BSs may have
different transmit power levels, different coverage areas, and
different impact on interference in wireless network 100. For
example, macro BSs may have a high transmit power level (e.g., 5 to
40 Watts) whereas pico BSs, femto BSs, and relay BSs may have lower
transmit power levels (e.g., 0.1 to 2 Watts).
A network controller 130 may couple to a set of BSs and may provide
coordination and control for these BSs. Network controller 130 may
communicate with the BSs via a backhaul. The BSs may also
communicate with one another, e.g., directly or indirectly via a
wireless or wireline backhaul.
UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout
wireless network 100, and each UE may be stationary or mobile. A UE
may also be referred to as an access terminal, a terminal, a mobile
station, a subscriber unit, a station, and/or the like. A UE may be
a cellular phone (e.g., a smart phone), a personal digital
assistant (PDA), a wireless modem, a wireless communication device,
a handheld device, a laptop computer, a cordless phone, a wireless
local loop (WLL) station, a tablet, a camera, a gaming device, a
netbook, a smartbook, an ultrabook, medical device or equipment,
biometric sensors/devices, wearable devices (smart watches, smart
clothing, smart glasses, smart wrist bands, smart jewelry (e.g.,
smart ring, smart bracelet)), an entertainment device (e.g., a
music or video device, or a satellite radio), a vehicular component
or sensor, smart meters/sensors, industrial manufacturing
equipment, a global positioning system device, or any other
suitable device that is configured to communicate via a wireless or
wired medium.
Some UEs may be considered machine-type communication (MTC) or
evolved or enhanced machine-type communication (eMTC) UEs. MTC and
eMTC UEs include, for example, robots, drones, remote devices, such
as sensors, meters, monitors, location tags, and/or the like, that
may communicate with a base station, another device (e.g., remote
device), or some other entity. A wireless node may provide, for
example, connectivity for or to a network (e.g., a wide area
network such as Internet or a cellular network) via a wired or
wireless communication link. Some UEs may be considered
Internet-of-Things (IoT) devices, and/or may be implemented as may
be implemented as NB-IoT (narrowband internet of things) devices.
Some UEs may be considered a Customer Premises Equipment (CPE). UE
120 may be included inside a housing that houses components of UE
120, such as processor components, memory components, and/or the
like.
In general, any number of wireless networks may be deployed in a
given geographic area. Each wireless network may support a
particular RAT and may operate on one or more frequencies. A RAT
may also be referred to as a radio technology, an air interface,
and/or the like. A frequency may also be referred to as a carrier,
a frequency channel, and/or the like. Each frequency may support a
single RAT in a given geographic area in order to avoid
interference between wireless networks of different RATs. In some
cases, NR or 5G RAT networks may be deployed.
In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE
120e) may communicate directly using one or more sidelink channels
(e.g., without using a base station 110 as an intermediary to
communicate with one another). For example, the UEs 120 may
communicate using a vehicle-to-everything (V2X) protocol, which may
include a vehicle-to-vehicle (V2V) protocol, a
vehicle-to-infrastructure (V2I) protocol, and/or the like. In this
case, the UE 120 may perform scheduling operations, resource
selection operations, and/or other operations described elsewhere
herein as being performed by the base station 110. In some aspects,
a UE 120 may operate in transmission mode 3, where resource
selection and/or scheduling is performed by the base station 110.
In some aspects, a UE 120 may operate in transmission mode 4, where
resource selection and/or scheduling is performed by the UE 120.
Additional details regarding sidelink communications and V2X
communications are described below in connection with FIG. 3.
As shown in FIG. 1, the UE 120 may include a communication manager
140. As described in more detail elsewhere herein, the
communication manager 140 may determine a limit on a number of
resource blocks (RBs) permitted to be used for a V2X transmission
by the UE 120, may determine one or more parameters for the V2X
transmission based at least in part on the limit, may transmit the
V2X transmission based at least in part on the one or more
parameters, and/or the like. Additionally, or alternatively, the
communication manager 140 may perform one or more other operations
described herein.
As indicated above, FIG. 1 is provided merely as an example. Other
examples are possible and may differ from what was described with
regard to FIG. 1.
FIG. 2 shows a block diagram of a design of base station 110 and UE
120, which may be one of the base stations and one of the UEs in
FIG. 1. Base station 110 may be equipped with T antennas 234a
through 234t, and UE 120 may be equipped with R antennas 252a
through 252r, where in general T.gtoreq.1 and R.gtoreq.1.
At base station 110, a transmit processor 220 may receive data from
a data source 212 for one or more UEs, select one or more
modulation and coding schemes (MCS) for each UE based at least in
part on channel quality indicators (CQIs) received from the UE,
process (e.g., encode and modulate) the data for each UE based at
least in part on the MCS(s) selected for the UE, and provide data
symbols for all UEs. Transmit processor 220 may also process system
information (e.g., for semi-static resource partitioning
information (SRPI) and/or the like) and control information (e.g.,
CQI requests, grants, upper layer signaling, and/or the like) and
provide overhead symbols and control symbols. Transmit processor
220 may also generate reference symbols for reference signals
(e.g., the cell-specific reference signal (CRS)) and
synchronization signals (e.g., the primary synchronization signal
(PSS) and secondary synchronization signal (SSS)). A transmit (TX)
multiple-input multiple-output (MIMO) processor 230 may perform
spatial processing (e.g., precoding) on the data symbols, the
control symbols, the overhead symbols, and/or the reference
symbols, if applicable, and may provide T output symbol streams to
T modulators (MODs) 232a through 232t. Each modulator 232 may
process a respective output symbol stream (e.g., for OFDM and/or
the like) to obtain an output sample stream. Each modulator 232 may
further process (e.g., convert to analog, amplify, filter, and
upconvert) the output sample stream to obtain a downlink signal. T
downlink signals from modulators 232a through 232t may be
transmitted via T antennas 234a through 234t, respectively.
According to certain aspects described in more detail below, the
synchronization signals can be generated with location encoding to
convey additional information.
At UE 120, antennas 252a through 252r may receive the downlink
signals from base station 110 and/or other base stations and may
provide received signals to demodulators (DEMODs) 254a through
254r, respectively. Each demodulator 254 may condition (e.g.,
filter, amplify, downconvert, and digitize) a received signal to
obtain input samples. Each demodulator 254 may further process the
input samples (e.g., for OFDM and/or the like) to obtain received
symbols. A MIMO detector 256 may obtain received symbols from all R
demodulators 254a through 254r, perform MIMO detection on the
received symbols if applicable, and provide detected symbols. A
receive processor 258 may process (e.g., demodulate and decode) the
detected symbols, provide decoded data for UE 120 to a data sink
260, and provide decoded control information and system information
to a controller/processor 280. A channel processor may determine
reference signal received power (RSRP), received signal strength
indicator (RSSI), reference signal received quality (RSRQ), channel
quality indicator (CQI), and/or the like.
On the uplink, at UE 120, a transmit processor 264 may receive and
process data from a data source 262 and control information (e.g.,
for reports comprising RSRP, RSSI, RSRQ, CQI, and/or the like) from
controller/processor 280. Transmit processor 264 may also generate
reference symbols for one or more reference signals. The symbols
from transmit processor 264 may be precoded by a TX MIMO processor
266 if applicable, further processed by modulators 254a through
254r (e.g., for DFT-s-OFDM, CP-OFDM, and/or the like), and
transmitted to base station 110. At base station 110, the uplink
signals from UE 120 and other UEs may be received by antennas 234,
processed by demodulators 232, detected by a MIMO detector 236 if
applicable, and further processed by a receive processor 238 to
obtain decoded data and control information sent by UE 120. Receive
processor 238 may provide the decoded data to a data sink 239 and
the decoded control information to controller/processor 240. Base
station 110 may include communication unit 244 and communicate to
network controller 130 via communication unit 244. Network
controller 130 may include communication unit 294,
controller/processor 290, and memory 292.
Although FIG. 2 illustrates components of a base station 110, a UE
120, and a network controller 130 for completeness, in some
aspects, two or more UEs 120 may communicate directly with one
another via a sidelink (e.g., without communicating with a base
station 110 as an intermediary). In this case, one or more
components of the UE 120 may perform one or more operations or
functions described herein as being performed by one or more
components of the base station 110 (e.g., for scheduling, resource
selection, and/or the like). Additional details regarding direct
UE-to-UE communications are described below in connection with FIG.
3.
In some aspects, one or more components of UE 120 may be included
in a housing. Controller/processor 280 of UE 120 and/or any other
component(s) of FIG. 2 may perform one or more techniques
associated with autonomous resource selection for V2X
transmissions, as described in more detail elsewhere herein. For
example, controller/processor 280 of UE 120 and/or any other
component(s) of FIG. 2 may perform or direct operations of, for
example, process 600 of FIG. 6 and/or other processes as described
herein. Memories 242 and 282 may store data and program codes for
base station 110 and UE 120, respectively. A scheduler 246 may
schedule UEs for data transmission on the downlink and/or
uplink.
In some aspects, the UE 120 may include means for determining a
limit on a number of resource blocks (RBs) permitted to be used for
a V2X transmission by the UE 120, means for determining one or more
parameters for the V2X transmission based at least in part on the
limit, means for transmitting the V2X transmission based at least
in part on the one or more parameters, and/or the like.
Additionally, or alternatively, the UE 120 may include means for
performing one or more other operations described herein. In some
aspects, such means may include the communication manager 140.
Additionally, or alternatively, such means may include one or more
components of the UE 120 described in connection with FIG. 2.
As indicated above, FIG. 2 is provided merely as an example. Other
examples are possible and may differ from what was described with
regard to FIG. 2.
FIG. 3 is a block diagram conceptually illustrating an example 300
of V2X communications via a sidelink, in accordance with certain
aspects of the present disclosure.
As shown in FIG. 3, a first UE 305-1 may communicate with a second
UE 305-2 (and one or more other UEs 305) using device-to-device
(D2D) communications via one or more sidelink channels 310. In some
aspects, the UEs 305 may correspond to one or more other UEs
described elsewhere herein, such as UE 120 and/or the like. In some
aspects, the sidelink channel 310 may use a PC5 interface and/or
may operate in a high frequency band (e.g., the 5.9 GHz band).
Additionally, or alternatively, the UEs 305 may synchronize timing
of transmission time intervals (e.g., frames, subframes, slots,
and/or the like) using global navigation satellite system (GNSS)
timing. The UEs 305 may transmit V2X communications using the
sidelink channel 310.
In some aspects, V2X transmissions may be one-to-many broadcast
and/or multicast transmissions. In some aspects, V2X transmissions
may not require any physical layer feedback from receiving devices,
such as acknowledgement (ACK) or negative acknowledgement (NACK)
feedback. In some aspects, V2X transmissions may be configured
without retransmission. In some aspects, V2X transmissions may be
configured with a small number of retransmissions (e.g., one
retransmission) that always occur (e.g., without ACK/NACK
feedback).
As further shown in FIG. 3, the sidelink channel 310 may include a
physical sidelink control channel (PSCCH) 315 and a physical
sidelink shared channel (PSSCH) 320. The PSCCH 315 may be used to
communicate control information, similar to a physical downlink
control channel (PDCCH) and/or a physical uplink control channel
(PUCCH) used for communications with a base station 110. The PSSCH
320 may be used to communicate data, similar to a physical downlink
shared channel (PDSCH) and/or a physical uplink shared channel
(PUSCH) used for communications with a base station 110. For
example, the PSCCH 315 may carry sidelink control information (SCI)
325, which may indicate various control information used for
sidelink communications, such as one or more resources (e.g., time
and/or frequency resources) where a transport block (TB) 330 that
includes data is carried on the PSSCH 320. The TB 330 may include
V2X data, such as a basic safety message (BSM), a traffic
information message (TIM), a signal phase and time (SPAT) message,
a MAP message to convey geographic road information, a cooperative
awareness message (CAM), a distributed environment notification
message (DENM), an in-vehicle information (IVI) message, and/or the
like.
In some aspects, the sidelink channel 310 may use resource pools.
For example, a scheduling assignment (e.g., included in SCI 325)
may be transmitted in sub-channels using specific resource blocks
(RBs) across time. In some aspects, data transmissions (e.g., on
the PSSCH 320) associated with a scheduling assignment may occupy
adjacent RBs in the same subframe as the scheduling assignment
(e.g., using frequency division multiplexing). In some aspects, a
scheduling assignment and associated data transmissions are not
transmitted on adjacent RBs.
In some aspects, a UE 305 may operate using transmission mode 4,
where resource selection and/or scheduling is performed by the UE
305 (e.g., rather than a base station 110). In some aspects, the UE
305 may perform resource selection and/or scheduling by sensing
channel availability for transmissions. For example, the UE 305 may
measure a received signal strength indicator (RSSI) parameter
(e.g., a sidelink-RSSI (S-RSSI) parameter) associated with various
sidelink channels, may measure a reference signal received power
(RSRP) parameter (e.g., a PSSCH-RSRP parameter) associated with
various sidelink channels, may measure a reference signal received
quality (RSRQ) parameter (e.g., a PSSCH-RSRQ parameter) associated
with various sidelink channels, and/or the like, and may select a
channel for transmission of V2X communications based at least in
part on the measurement(s).
Additionally, or alternatively, the UE 305 may perform resource
selection and/or scheduling using SCI 325 received in the PSCCH
315, which may indicate occupied resources, channel parameters,
and/or the like. Additionally, or alternatively, the UE 305 may
perform resource selection and/or scheduling by determining a
channel busy rate (CBR) associated with various sidelink channels,
which may be used for rate control (e.g., by indicating a maximum
number of resource blocks that the UE 305 can use for a particular
set of subframes).
In transmission mode 4, a UE 305 may generate sidelink grants, and
may transmit the grants in SCI 325. A sidelink grant may indicate,
for example, one or more parameters (e.g., transmission parameters)
to be used for an upcoming V2X transmission, such as one or more
resource blocks to be used for the upcoming V2X transmission on the
PSSCH 320 (e.g., for TBs 330), one or more subframes to be used for
the upcoming V2X transmission, a modulation and coding scheme (MCS)
to be used for the upcoming V2X transmission, and/or the like. In
some aspects, a UE 305 may generate a sidelink grant that indicates
one or more parameters for semi-persistent scheduling (SPS), such
as a periodicity of a V2X transmission (e.g., a periodic V2X
message, such as a safety message and/or the like). Additionally,
or alternatively, the UE 305 may generate a sidelink grant for
event-driven scheduling, such as for an on-demand V2X message.
In V2X communication systems, conditions of the sidelink channel
310 used to carry V2X communications can vary widely and change
quickly due to the high mobility of vehicles and UEs associated
with the vehicles, large variations in vehicle traffic at different
times of day and in different locations, a wide variety of
topographies that the vehicles may traverse (e.g., dense urban
environments, hilly environments, flat environments, etc.), and/or
the like. Furthermore, V2X communication systems need to be highly
reliable due to mission critical safety issues associated with, for
example, autonomous vehicles. Some techniques and apparatuses
described herein improve performance of V2X communication systems
by dynamically determining parameters for V2X transmissions based
at least in part on dynamic factors associated with one or more
vehicles, the sidelink channel 310, and/or the like.
As indicated above, FIG. 3 is provided merely as an example. Other
examples are possible and may differ from what was described with
regard to FIG. 3.
FIG. 4 is a diagram illustrating an example 400 of autonomous
resource selection for V2X transmissions, in accordance with
various aspects of the present disclosure.
As shown in FIG. 4, a first UE 405-1 may communicate with a second
UE 405-2 (and one or more other UEs 405) via one or more sidelink
channels 410. In some aspects, the UEs 405 may correspond to one or
more other UEs described elsewhere herein, such as UE 120, UE 305,
and/or the like. In some aspects, the sidelink channel 410 may
correspond to one or more sidelink channels described elsewhere
herein, such as sidelink channel 310 and/or the like. In some
aspects, a UE 405 may be associated with a vehicle 415 (e.g., may
be integrated into the vehicle 415, may be located in or on the
vehicle 415, and/or the like). The vehicle 415 may include an
autonomous vehicle, a semi-autonomous vehicle, a non-autonomous
vehicle, and/or the like. Although both UEs 405 in FIG. 4 are shown
as being associated with a vehicle 415, in some aspects, one or
more of the UEs 405 may not be associated with a vehicle 415. For
example, a UE 405 may be associated with infrastructure (e.g.,
traffic infrastructure), such as a traffic signal, a lane signal, a
sensor, a traffic controller system, and/or the like.
As shown by reference number 420, the first UE 405-1 may determine
a limit on a number of resource blocks (RBs) permitted to be used
for a V2X transmission by the first UE 405-1. In some aspects, the
first UE 405-1 may determine the limit based at least in part on a
congestion level of one or more sidelink channels, which may be
determined based at least in part on measuring one or more sidelink
channels (e.g., for S-RSSI, PSSCH-RSRP, and/or the like), receiving
SCI associated with the one or more sidelink channels, and/or the
like. For example, the first UE 405-1 may determine a channel busy
rate (CBR) for a sidelink channel in association with a time n at
which resource selection is triggered for the first UE 405-1 (e.g.,
CBR(n-100, n-1), where n-100 denotes a start of a time period and
n-1 denotes the end of the time period), and may determine a
maximum number of RBs allowed for use by the first UE 405-1 at time
n based at least in part on the CBR. Additionally, or
alternatively, the first UE 405-1 may determine the limit on the
number of RBs by determining a maximum number of RBs allowed for
use by the first UE 405-1 in association with time n (e.g.,
CR.sub.limit(n)) and subtracting a number of RBs already used or
scheduled by the first UE 405-1 in association with time n (e.g.,
CR(n-a, n+b), where n-a denotes a start of the time period and n+b
denotes an end of the time period).
As shown by reference number 425, the first UE 405-1 may determine
one or more parameters for the V2X transmission based at least in
part on the limit on the number of RBs. In some aspects, the one or
more parameters may be referred to as one or more transmission
parameters and/or one or more V2X transmission parameters. As
shown, the one or more parameters may include a modulation and
coding scheme (MCS) for the V2X transmission, a number of transport
blocks (TBs) for the V2X transmission, a number of RBs per TB for
the V2X transmission, a retransmission configuration for the V2X
transmission, and/or the like. In some aspects, the first UE 405-1
may determine the one or more parameters such that the number of
RBs for the V2X transmission does not exceed the limit on the
number of RBs.
As an example, if the first UE 405-1 selects an MCS with a lower
index value (e.g., permitting fewer bits per symbol) for a V2X
transmission, then that V2X transmission would require more TBs and
corresponding RBs than if the same V2X transmission were to use an
MCS with a higher index value (e.g., permitting more bits per
symbol). However, using an MCS with a lower index value for the V2X
transmission may increase the range of the V2X transmission and/or
may increase reliability of the V2X transmission as compared to
using an MCS with a higher index value. Thus, in some aspects, if
the limit on the number of RBs is relatively high (e.g., greater
than or equal to a threshold), then the first UE 405-1 may select
an MCS with a lower index value, and if the limit on the number of
RBs is relatively low (e.g., less than or equal to a threshold),
then the first UE 405-1 may select an MCS with a higher index
value. In some aspects, the first UE 405-1 may select from multiple
different MCS index values, and different MCS index values may be
associated with different thresholds for the limit on the number of
RBs.
As another example, if the first UE 405-1 configures a
retransmission configuration to enable retransmissions for a V2X
transmission, then that V2X transmission would require more TBs and
corresponding RBs than if the first UE 405-1 were to configure the
retransmission configuration to disable retransmissions for the
same V2X transmission. However, enabling retransmissions for the
V2X transmission may increase the range of the V2X transmission
and/or may increase reliability of the V2X transmission as compared
to disabling retransmissions for the V2X transmission. Thus, in
some aspects, if the limit on the number of RBs is relatively high
(e.g., greater than or equal to a threshold), then the first UE
405-1 may enable retransmissions, and if the limit on the number of
RBs is relatively low (e.g., less than or equal to a threshold),
then the first UE 405-1 may disable retransmissions. In some
aspects, the first UE 405-1 may select from multiple different
quantities of retransmissions (e.g., one retransmission, two
retransmissions, etc.), and different quantities of retransmissions
may be associated with different thresholds for the limit on the
number of RBs.
In some aspects, the first UE 405-1 may select the one or more
parameters to increase or maximize a range for the V2X transmission
(e.g., a distance that can be covered by the V2X transmission and
corresponding retransmissions) subject to the limit on the number
of RBs, as described in more detail below in connection with FIG.
5. In this way, the first UE 405-1 may improve reliability, may
increase safety, may increase the likelihood of successful
reception of the V2X transmission, etc., while operating according
to the limit on the number of RBs permitted for the V2X
transmission.
In a V2X communication system, sidelink channel conditions can vary
widely at different times, at different geographic locations, on
different frequencies, and/or the like. Thus, the first UE 405-1
may dynamically determine the one or more parameters for the V2X
transmission based at least in part on conditions that exist at the
time that the V2X transmission is scheduled. In some aspects, the
first UE 405-1 may determine the one or more transmission
parameters based at least in part on a dynamic factor associated
with the first UE 405-1 and/or a vehicle associated with the first
UE 405-1 (e.g., a network traffic demand associated with one or
more applications of the first UE 405-1, a speed or velocity of the
first UE 405-1, a location of the first UE 405-1, a topography of
the location, and/or the like). Additionally, or alternatively, the
first UE 405-1 may determine the one or more transmission
parameters based at least in part on a dynamic factor associated
with a wireless network via which the V2X transmission is to be
transmitted (e.g., a congestion level associated with the wireless
network, a carrier frequency on which the V2X transmission is to be
transmitted, a priority of the V2X transmission on the wireless
network, and/or the like). In this way, the first UE 405-1 may
improve or optimize transmission of V2X messages under changing
conditions.
In some aspects, the first UE 405-1 may be capable of selecting one
or more frequencies to carry the V2X transmission, and may
determine the one or more parameters based at least in part on the
selected frequency or frequencies. For example, a range of the V2X
transmission may depend on a frequency used to transmit the V2X
transmission (e.g., a lower frequency may have a higher range and a
higher frequency may have a lower range). In some aspects, the
first UE 405-1 may select a frequency for the V2X transmission
based at least in part on an estimated range associated with the
frequency (e.g., by prioritizing a lower frequency over a higher
frequency).
Additionally, or alternatively, the first UE 405-1 may determine
the one or more V2X transmission parameters based at least in part
on the selected frequency or frequencies. For example, different
frequencies may be associated with different CBR values, and thus
may be associated with different limits on the number of RBs
permitted for use by the first UE 405-1. Additionally, or
alternatively, different combinations of transmission parameters
may result in different performance at different frequencies, and
the first UE 405-1 may use this as a factor when determining the
one or more transmission parameters.
In some aspects, the first UE 405-1 may determine the one or more
transmission parameters based at least in part on a network traffic
demand associated with one or more applications of the first UE
405-1. For example, if the first UE 405-1 has a relatively high
network traffic demand (e.g., the number of requested V2X
transmissions is greater than or equal to a threshold), then the
first UE 405-1 may use a smaller number of RBs per V2X
transmission. Conversely, if the first UE 405-1 has a relatively
low network traffic demand (e.g., the number of requested V2X
transmissions is less than or equal to a threshold), then the first
UE 405-1 may use a larger number of RBs per V2X transmission. The
first UE 405-1 may configure a smaller number of RBs per V2X
transmission by using a higher MCS index, by disabling
retransmissions or configuring a smaller number of retransmissions,
by using a smaller number of TBs, and/or by using a smaller number
of RBs per TB. Conversely, the first UE 405-1 may configure a
larger number of RBs per V2X transmission by using a lower MCS
index, by enabling retransmissions or configuring a larger number
of retransmissions, by using a larger number of TBs, and/or by
using a larger number of RBs per TB.
Additionally, or alternatively, the first UE 405-1 may determine
the one or more transmission parameters based at least in part on a
congestion level associated with a wireless network via which the
V2X transmission is to be transmitted (e.g., a congestion level of
the sidelink channel 410 and/or one or more frequencies via which
the V2X transmission is to be transmitted). For example, if the
wireless network has a relatively high congestion level, then the
first UE 405-1 may use a smaller number of RBs per V2X
transmission. Conversely, if the wireless network has a relatively
low congestion level, then the first UE 405-1 may use a larger
number of RBs per V2X transmission. In some aspects, the first UE
405-1 may determine the congestion level based at least in part on
a CBR, a resource restriction (e.g., a rate control parameter, a
power control parameter, a congestion control parameter, etc.), a
measured parameter of the wireless network (e.g., an energy level),
and/or the like.
Additionally, or alternatively, the first UE 405-1 may determine
the one or more parameters based at least in part on a priority of
the V2X transmission. For example, the first UE 405-1 may select
one or more parameters that result in a higher transmission range
for a high priority packet, and may select one or more parameters
that result in a lower transmission range for a low priority
packet.
Additionally, or alternatively, the first UE 405-1 may determine
the one or more parameters based at least in part on a velocity of
the first UE 405-1 (e.g., a velocity at the time of scheduling the
V2X transmission), which may correspond to a velocity of a vehicle
415 associated with the first UE 405-1. In some aspects,
demodulation may be challenging at high speeds due to Doppler
shift. Thus, the first UE 405-1 may select a lower MCS index for
V2X transmission when the first UE 405-1 is traveling at a high
velocity (e.g., greater than or equal to a threshold velocity).
Conversely, the first UE 405-1 may select a higher MCS index for
V2X transmission when the first UE 405-1 is traveling at a low
velocity (e.g., less than or equal to a threshold velocity). In
some aspects, the first UE 405-1 may select from multiple different
MCS index values, and different MCS index values may be associated
with different thresholds for the velocity of the first UE
405-1.
Additionally, or alternatively, the first UE 405-1 may determine
the one or more parameters based at least in part on a topography
associated with a location of the first UE 405-1. For example,
different combinations of parameters may result in different
performance in different topographies, and the first UE 405-1 may
select a combination of parameters that provides better performance
(e.g., increased range) as compared to another combination of
parameters. In some aspects, the first UE 405-1 and/or a vehicle
associated with the first UE 405-1 may detect the topography (e.g.,
using LIDAR and/or the like).
Additionally, or alternatively, the first UE 405-1 may determine
the one or more parameters based at least in part a location of the
first UE 405-1. In some aspects, performance of different
combinations of parameters may be measured over time (e.g., by one
or more UEs 405) in different locations, and/or may be indicated to
one or more UEs 405. In some aspects, the UE 405 may store
information indicating one or more parameters to be used in a
location based at least in part on historical performance of those
parameters in that location.
Additionally, or alternatively, the first UE 405-1 may determine
the one or more parameters based at least in part on a number of
bits of the V2X transmission (e.g., which impacts a number of RBs
needed for the V2X transmission), a deadline for transmission of
the V2X transmission (e.g., which may impact a determination of
whether to wait for improved channel conditions and transmit with a
larger range, whether to transmit sooner with shorter range, and/or
the like), a semi-persistent scheduling period associated with the
V2X transmission (e.g., which may be used to determine RBs for
periodic V2X transmissions), and/or the like.
As shown by reference number 430, the first UE 405-1 may transmit
the V2X transmission (e.g., to the second UE 405-2 and/or one or
more other UEs 405) based at least in part on the one or more
parameters. For example, the first UE 405-1 may modulate and/or
encode the V2X transmission using a selected MCS, may transmit the
V2X transmission using a selected number of TBs, may transmit the
V2X transmission using a selected number of RBs per TB, may
retransmit or prevent retransmission of the V2X transmission
according to a selected retransmission configuration, may transmit
the V2X transmission on a selected carrier frequency, and/or the
like. By accounting for dynamic factors when determining the above
transmission parameter(s), the first UE 405-1 may improve
performance (e.g., a transmission range) of the V2X transmission
subject to constraints on the V2X transmission. For example, in
some cases, the first UE 405-1 may transmit a V2X transmission
using an MCS with a high index, rather than dropping the V2X
transmission.
As indicated above, FIG. 4 is provided merely as an example. Other
examples are possible and may differ from what was described with
regard to FIG. 4.
FIG. 5 is a diagram illustrating an example 500 of autonomous
resource selection for V2X transmissions, in accordance with
various aspects of the present disclosure.
As shown in FIG. 5, a first UE 505-1 may communicate with a second
UE 505-2 (and one or more other UEs 505) via one or more sidelink
channels 510. In some aspects, the UEs 505 may correspond to one or
more other UEs described elsewhere herein, such as UE 120, UE 305,
UE 405, and/or the like. In some aspects, the sidelink channel 510
may correspond to one or more sidelink channels described elsewhere
herein, such as sidelink channel 310, sidelink channel 410, and/or
the like. In some aspects, a UE 505 may be associated with a
vehicle and/or infrastructure, as described above in connection
with FIG. 4.
As shown by reference number 515, the first UE 505-1 may determine
a limit on a number of RBs permitted to be used for a V2X
transmission by the first UE 505-1, as described above in
connection with FIG. 4.
As shown by reference number 520, the first UE 505-1 may determine
multiple combinations of parameters to potentially be used for the
V2X transmission. Two different combinations may include at least
one parameter that is different between the two different
combinations, such as a different MCS, a different number of TBs, a
different number of RBs per TB, a different retransmission
configuration (e.g., disabled, enabled, enabled with one
retransmission, enabled with two retransmissions, and/or the like),
a different carrier frequency, and/or the like.
In some aspects, the first UE 505-1 may disable retransmission of
the V2X transmission, and may select a lowest MCS value (e.g., a
lowest MCS index) that satisfies the limit on the number of RBs
with retransmission disabled, thereby improving or maximizing the
range of the V2X transmission subject to the limit on the number of
RBs. As an example, the first UE 505-1 may determine a first set of
parameters 525 that includes an MCS index of 1 (e.g., a lower index
with a lower data rate and fewer bits per symbol), 9 TBs, a set of
RBs per TB shown as {X.sub.1, . . . , X.sub.9}, and a
retransmission configuration that disables retransmissions. In some
aspects, the first UE 505-1 may select the lowest MCS value that
does not fall below a default or minimum MCS value to be used by
the first UE 505-1.
In some aspects, the first UE 505-1 may enable retransmission of
the V2X transmission, and may select a lowest MCS value (e.g., a
lowest MCS index) that satisfies the limit on the number of RBs
with retransmission enabled, thereby improving or maximizing the
range of the V2X transmission subject to the limit on the number of
RBs. As an example, the first UE 505-1 may determine a second set
of parameters 530 that includes an MCS index of 4 (e.g., a higher
index with a higher data rate and more bits per symbol), 3 TBs, a
set of RBs per TB shown as {Y.sub.1, . . . , Y.sub.3}, and a
retransmission configuration that enables retransmissions. In some
aspects, the first UE 505-1 may select the lowest MCS value that
does not fall below a default or minimum MCS value to be used by
the first UE 505-1.
As shown by reference number 535, the first UE 505-1 may select a
combination of parameters for the V2X transmission based at least
in part on comparing characteristics associated with the multiple
combinations. For example, the first UE 505-1 may select a
combination of parameters based at least in part on different RB
requirements associated with the different combinations, based at
least in part on a peak MCS associated with the first UE 505-1,
based at least in part on different ranges associated with the
different combinations, and/or the like.
In some aspects, the first UE 505-1 may select a combination of
parameters based at least in part on different RB requirements
associated with the different combinations of parameters. For
example, the first UE 505-1 may determine a plurality of resource
block requirements corresponding to a plurality of combinations of
parameters (e.g., one or more of MCS, number of TBs, number of RBs
per TB, and retransmission configuration) for the V2X transmission.
The first UE 505-1 may select a combination of parameters based at
least in part on comparing the plurality of resource block
requirements to the limit on the number of RBs. For example, if a
combination of parameters requires a number of RBs that exceeds the
limit, then the first UE 505-1 may not select that combination of
parameters. Conversely, if a combination of parameters requires a
number of RBs that is less than or equal to the limit, then the
first UE 505-1 may select that combination of parameters. If
multiple combinations of parameters satisfy the resource block
limit, then the first UE 505-1 may use one or more other
characteristics of the combinations to select a combination. For
example, the first UE 505-1 may select a combination that uses the
least number of RBs, that has the longest range, that includes an
MCS value that is less than a peak MCS value associated with the
first UE 505-1, that is most similar to a default combination of
parameters associated with the first UE 505-1, and/or the like.
In some aspects, the first UE 505-1 may select a combination of
parameters based at least in part on a peak MCS permitted to be
used by the first UE 505-1 (e.g., due to hardware limitations of
the first UE 505-1, due to a peak MCS defined in a 3GPP standard,
and/or the like). For example, if a combination of parameters
includes an MCS that exceeds a peak MCS permitted to be used by the
first UE 505-1, then the first UE 505-1 may not select that
combination of parameters. Conversely, if a combination of
parameters includes an MCS that does not exceed a peak MCS
permitted to be used by the first UE 505-1, then the first UE 505-1
may select that combination of parameters. If multiple combinations
of parameters satisfy the peak MCS constraint, then the first UE
505-1 may use one or more other characteristics of the combinations
to select a combination. For example, the first UE 505-1 may select
a combination that satisfies the limit on the number of RBs, that
uses the least number of RBs, that has the longest range, that is
most similar to a default combination of parameters associated with
the first UE 505-1, and/or the like.
As an example, the first UE 505-1 may determine a first combination
of parameters that satisfies the limit on the number of RBs.
However, the first UE 505-1 may determine that a first MCS,
included in the first combination of parameters, exceeds a peak MCS
permitted to be used by the first UE 505-1. In this case, the first
UE 505-1 may determine a second combination of parameters, that
includes a second MCS, based at least in part on determining that
that the first MCS exceeds the peak MCS. The first UE 505-1 may
determine that the second MCS does not exceed the peak MCS, and may
transmit the V2X transmission using the second MCS based at least
in part on determining that the second MCS does not exceed the peak
MCS. In some aspects, the first UE 505-1 may select the first MCS
due to a condition that results in a lower limit on the number of
RBs (e.g., poor channel conditions, high network traffic
conditions, a large amount of data to be transmitted by the first
UE 505-1, and/or the like). In this case, the first UE 505-1 may
determine the second combination of parameters after waiting a
threshold amount of time (e.g., after which the constraint may be
less strict, resulting in a higher limit on the number of RBs).
Additionally, or alternatively, the first UE 505-1 may determine
the second combination of parameters after determining that the
condition associated with the limit on the number of RBs has
changed (e.g., has relaxed).
In some aspects, the first UE 505-1 may select a combination of
parameters to increase or maximize a range for the V2X transmission
subject to the limit on the number of RBs. Additionally, or
alternatively, the first UE 505-1 may select a combination of
parameters that has a longer range as compared to another
combination of parameters. For example, the first UE 505-1 may
determine a first set of parameters, may determine a second set of
parameters, may estimate a first range for the V2X transmission
using the first set of parameters, may estimate a second range for
the V2X transmission using the second set of parameters, may
compare the first range and the second range, and may select the
set of parameters associated with the longer range. In some
aspects, the first set of parameters may include a first MCS (e.g.,
with a higher MCS index) that satisfies the limit on the number of
RBs with the retransmission configuration configured to enable
retransmission of the V2X transmission, and the second set of
parameters may include a second MCS (e.g., with a lower MCS index)
that satisfies the limit on the number of RBs with the
retransmission configuration configured to disable retransmission
of the V2X transmission.
In some aspects, the first UE 505-1 may select a combination of
parameters based at least in part on one or more default parameters
and/or a default combination of parameters (e.g., one or more
preferred parameters). For example, the first UE 505-1 may select a
combination of parameters based at least in part on a default MCS,
a default preference for the number of TBs (e.g., a larger number
of TBs or a fewer number of TBs), a default preference for the
number of RBs per TB, a default retransmission configuration (e.g.,
enabled by default, disabled by default, and/or the like), and/or
the like. In some aspects, the first UE 505-1 may initially test
whether the default combination of parameters satisfies the limit
on the number of RBs (e.g., before testing any other combination of
parameters). If the default combination of parameters satisfies the
limit on the number of RBs, then the first UE 505-1 may use the
default combination of parameters for the V2X transmission. If the
default combination of parameters does not satisfy the limit on the
number of RBs, then the first UE 505-1 may test another combination
of parameters (e.g., with a higher MCS index, with retransmissions
disabled, with a smaller number of TBs, with a smaller number of
RBs per TB, and/or the like). In this way, the first UE 505-1 may
conserve UE resources (e.g., processing power, memory, battery
power, and/or the like) as compared to always testing multiple
combinations of parameters for the V2X transmission.
As shown by reference number 540, the first UE 505-1 may transmit
the V2X transmission (e.g., to the second UE 505-2 and/or one or
more other UEs 505) using the selected combination of parameters,
in a similar manner as described above in connection with FIG. 4.
In this way, the first UE 505-1 may improve reliability, may
increase safety, may increase the likelihood of successful
reception of the V2X transmission, etc., while operating according
to the limit on the number of RBs permitted for the V2X
transmission.
As indicated above, FIG. 5 is provided merely as an example. Other
examples are possible and may differ from what was described with
regard to FIG. 5.
FIG. 6 is a diagram illustrating an example process 600 performed,
for example, by a UE, in accordance with various aspects of the
present disclosure. Example process 600 is an example where a UE
(e.g., UE 120, UE 405, UE 505, and/or the like) performs autonomous
resource selection for V2X transmissions.
As shown in FIG. 6, in some aspects, process 600 may include
determining a limit on a number of resource blocks (RBs) permitted
to be used for a vehicle-to-everything (V2X) transmission by the UE
(block 610). For example, the UE may determine a limit on a number
of RBs permitted to be used for a V2X transmission by the UE, as
described above in connection with FIGS. 4 and 5. In some aspects,
the limit is determined based at least in part on a congestion
level of a sidelink channel via which the V2X transmission is to be
transmitted.
As further shown in FIG. 6, in some aspects, process 600 may
include determining, based at least in part on the limit, one or
more parameters for the V2X transmission, wherein the one or more
parameters include at least one of a modulation and coding scheme
(MCS) for the V2X transmission, a number of transport blocks (TBs)
for the V2X transmission, a number of RBs per TB for the V2X
transmission, or a retransmission configuration for the V2X
transmission (block 620). For example, the UE may determine one or
more parameters for the V2X transmission, as described above in
connection with FIGS. 4 and 5. In some aspects, the UE may
determine the one or more parameters based at least in part on the
limit on the number of RBs. In some aspects, the one or more
parameters may include at least one of an MCS for the V2X
transmission, a number of TBs for the V2X transmission, a number of
RBs per TB for the V2X transmission, or a retransmission
configuration for the V2X transmission.
As further shown in FIG. 6, in some aspects, process 600 may
include transmitting the V2X transmission based at least in part on
the one or more parameters (block 630). For example, the UE may
transmit the V2X transmission based at least in part on the one or
more parameters, as described above in connection with FIGS. 4 and
5.
Process 600 may include additional aspects, such as any single
aspect or any combination of aspects described below.
In some aspects, the one or more parameters are determined for a
frequency selected by the UE for the V2X transmission. In some
aspects, the one or more parameters are determined based at least
in part on one or more dynamic factors associated with the UE or a
wireless network via which the V2X transmission is transmitted. In
some aspects, the one or more parameters are determined based at
least in part on a network traffic demand associated with one or
more applications of the UE. In some aspects, the one or more
parameters are determined based at least in part on a congestion
level associated with a wireless network via which the V2X
transmission is to be transmitted. In some aspects, the one or more
parameters are determined based at least in part on a carrier
frequency on which the V2X transmission is to be transmitted. In
some aspects, the one or more parameters are determined based at
least in part on a priority of the V2X transmission.
In some aspects, the one or more parameters are determined based at
least in part on a velocity of the UE. In some aspects, the one or
more parameters are determined based at least in part on a
topography of a location associated with the UE. In some aspects,
the one or more parameters are determined based at least in part on
a location of the UE. In some aspects, the one or more parameters
are selected to maximize a range of the V2X transmission subject to
the limit on the number of RBs. In some aspects, the one or more
parameters are determined based at least in part on at least one
of: a number of bits of the V2X transmission, a priority of the V2X
transmission, a deadline for transmission of the V2X transmission,
a semi-persistent scheduling period associated with the V2X
transmission, or some combination thereof. In some aspects, the one
or more parameters are determined based at least in part on a
default MCS associated with the UE.
In some aspects, the UE may determine a plurality of resource block
requirements corresponding to a plurality of combinations of MCS,
number of TBs, number of RBs per TB, and retransmission
configurations for the V2X transmission; and may determine the one
or more parameters based at least in part on comparing the
plurality of resource block requirements to the limit on the number
of RBs. In some aspects, the UE may determine that a first MCS
selected by the UE exceeds a peak MCS permitted to be used by the
UE; may determine the one or more parameters, including a second
MCS, based at least in part on determining that that the first MCS
exceeds the peak MCS; may determine that the second MCS does not
exceed the peak MCS; and may transmit the V2X transmission using
the second MCS based at least in part on determining that the
second MCS does not exceed the peak MCS. In some aspects, the
second MCS is determined after waiting a threshold amount of time
or determining that a channel condition is satisfied.
In some aspects, the retransmission configuration enables
retransmission of the V2X transmission and the UE is configured to
select a lowest MCS value that satisfies the limit on the number of
RBs with retransmission enabled. In some aspects, the
retransmission configuration disables retransmission of the V2X
transmission and the UE is configured to select a lowest MCS value
that satisfies the limit on the number of RBs with retransmission
disabled.
In some aspects, the UE may determine a first set of parameters
that includes a first MCS that satisfies the limit on the number of
RBs with the retransmission configuration configured to enable
retransmission of the V2X transmission; may determine a second set
of parameters that includes a second MCS that satisfies the limit
on the number of RBs with the retransmission configuration
configured to disable retransmission of the V2X transmission; may
estimate a first range for the V2X transmission using the first set
of parameters; and may estimate a second range for the V2X
transmission using the second set of parameters. In some aspects,
determining the one or more parameters for the V2X transmission
comprises selecting one of the first set of parameters or the
second set of parameters based at least in part on comparing the
first range and the second range.
Although FIG. 6 shows example blocks of process 600, in some
aspects, process 600 may include additional blocks, fewer blocks,
different blocks, or differently arranged blocks than those
depicted in FIG. 6. Additionally, or alternatively, two or more of
the blocks of process 600 may be performed in parallel.
The foregoing disclosure provides illustration and description, but
is not intended to be exhaustive or to limit the aspects to the
precise form disclosed. Modifications and variations are possible
in light of the above disclosure or may be acquired from practice
of the aspects.
As used herein, the term component is intended to be broadly
construed as hardware, firmware, or a combination of hardware and
software. As used herein, a processor is implemented in hardware,
firmware, or a combination of hardware and software.
Some aspects are described herein in connection with thresholds. As
used herein, satisfying a threshold may refer to a value being
greater than the threshold, greater than or equal to the threshold,
less than the threshold, less than or equal to the threshold, equal
to the threshold, not equal to the threshold, and/or the like.
It will be apparent that systems and/or methods, described herein,
may be implemented in different forms of hardware, firmware, or a
combination of hardware and software. The actual specialized
control hardware or software code used to implement these systems
and/or methods is not limiting of the aspects. Thus, the operation
and behavior of the systems and/or methods were described herein
without reference to specific software code--it being understood
that software and hardware can be designed to implement the systems
and/or methods based, at least in part, on the description
herein.
Even though particular combinations of features are recited in the
claims and/or disclosed in the specification, these combinations
are not intended to limit the disclosure of possible aspects. In
fact, many of these features may be combined in ways not
specifically recited in the claims and/or disclosed in the
specification. Although each dependent claim listed below may
directly depend on only one claim, the disclosure of possible
aspects includes each dependent claim in combination with every
other claim in the claim set. A phrase referring to "at least one
of" a list of items refers to any combination of those items,
including single members. As an example, "at least one of: a, b, or
c" is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well
as any combination with multiples of the same element (e.g., a-a,
a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and
c-c-c or any other ordering of a, b, and c).
No element, act, or instruction used herein should be construed as
critical or essential unless explicitly described as such. Also, as
used herein, the articles "a" and "an" are intended to include one
or more items, and may be used interchangeably with "one or more."
Furthermore, as used herein, the terms "set" and "group" are
intended to include one or more items (e.g., related items,
unrelated items, a combination of related and unrelated items,
and/or the like), and may be used interchangeably with "one or
more." Where only one item is intended, the term "one" or similar
language is used. Also, as used herein, the terms "has," "have,"
"having," and/or the like are intended to be open-ended terms.
Further, the phrase "based on" is intended to mean "based, at least
in part, on" unless explicitly stated otherwise.
* * * * *
References